In fact, Lochte's already getting the party started on his website -- selling "Jeah"-themed tees, hats, and sunglasses.

According to a 2009 interview, Ryan got the phrase from rapper Young Jeezy, who uses a similar word "Chea!" in his songs. Ryan says he changed it a little to "Jeah!" ... and says it means something "good." (skip to 1:00)